The large container (folded or unfolded structure) according to the present invention is a kind of logistics box, whose volume is generally above 600 L, and is widely used in logistics transportation and warehouse storage in various industries. Larger containers with volumes greater than 600 L typically have higher mechanical requirements and more complicated load-bearing design than smaller capacity containers.
The existing large containers generally have specifications such as 1200×1000×1000,1220×1220×1170 and so on, and the size is relative large. In order to facilitate to pick up goods inside the container, a small door is generally provided over the middle part of a side plate to further benefit the operation. However, the hinge connection of the side plate and the small door provided on the side plate of the existing large container is simple, which brings the side plate provided with a small door to a certain of loss in intensity while the small door provided on the side plate facilitate to take goods. When the small door on the side plate is opened, the anti-deformation ability of the whole side plate is weaken. As a consequence, the side plates of the container are more liable to bulge outward toward the outer edge of the box when the box has a full load. Such deformation will not only lead to the safety hazard of the production itself, but also in transportation lead to failure of loading a certain number of containers into the cargotainers with fixed dimension, for the gap between containers is narrowed or even does not exist upon loading. As disclosed in the published patent WO201001456, a small door is provided on the side plate of the container, and for the small door is connected to side plate only via a guide of the small door and the side plate, the connection structure is simple while the thickness of the small door is thin and the intensity of the small door is weak relative to the wall of the side plate, these two factors cause the small door not only fail to limit the upper stack container which brings security risks, but also increase the arranged mutual gap between the side plates of containers which indirectly increase the storage cost, due to tension applied on the side plate by the goods is liable to deform the side plates upon loading goods by the small door and the deformation results in the limitation failure of the side plates stack. Second, the substantially rectangular small door is arranged on the side plate, and its corresponding parts of the side plate adjacent to the small door are relatively isolated parts, which have a deeper longitudinal length and a narrower horizontal length, and thus the bending resistance ability and anti-pressure ability of these parts are so weak as to be easily deformed or broken in use, which increases the loss of products therefore directly increasing product maintenance cost. In addition, the substantially rectangular small door structure is provided on the side plate, the meshing link of the side plate and the small door is substantially vertical (i.e., the meshing is substantially along the same vertical line). Such arrangement is easy to cause that after the inner wall of small door bears the tension extruded outward by goods, the small door will rotate and deform along the common meshing vertical line (the middle part of the small door will deform and bulge relative to both ends). Furthermore, there exists tolerance gap of meshing between the small door and side plate, which make the deformation of both the small door and side plate part superimposed, resulting in the tendency of the small door more obvious. These factors likewise increase the breakage of the side plate and the small door, and meanwhile increase the logistics and warehousing costs, which result in significant wastage.